TN LLE Wiring Methods and Installation 1 — Questions and Answers
Question 1: According to NEC Table 300.5, what is the minimum burial depth for Type UF cable used for a 120/240V residential branch circuit?
- 6 inches
- 12 inches (Correct answer)
- 18 inches
- 24 inches
Correct answer: 12 inches
NEC Table 300.5 requires Type UF cable to be buried a minimum of 12 inches deep for residential branch circuits.
Question 2: Under NEC 300.4(A)(1), where cables pass through bored holes in wood framing, the edge of the hole must be at least how far from the nearest edge of the wood member (or a steel protective plate must be installed)?
- 1 inch
- 1-1/4 inches (Correct answer)
- 1-1/2 inches
- 2 inches
Correct answer: 1-1/4 inches
NEC 300.4(A)(1) requires the edge of bored holes to be at least 1-1/4 inches from the nearest edge of the wood member to protect cables from nails and screws.
Question 3: According to NEC 334.30, Type NM cable must be secured within how many inches of every cabinet, box, or fitting it enters?
- 6 inches
- 8 inches
- 12 inches (Correct answer)
- 18 inches
Correct answer: 12 inches
NEC 334.30 requires NM cable to be secured within 12 inches of every cabinet, box, or fitting.
Question 4: According to NEC 334.30, what is the maximum interval for securing and supporting Type NM cable in exposed locations?
- 2.5 feet
- 3 feet
- 4.5 feet (Correct answer)
- 6 feet
Correct answer: 4.5 feet
NEC 334.30 requires NM cable to be secured and supported at intervals not exceeding 4.5 feet in exposed locations.
Question 5: Which of the following wiring methods is NOT permitted in wet locations?
- Rigid Metal Conduit (RMC)
- Intermediate Metal Conduit (IMC)
- Type NM cable (Correct answer)
- Liquidtight Flexible Metal Conduit (LFMC)
Correct answer: Type NM cable
Type NM cable is prohibited in wet or damp locations per NEC 334.12; RMC, IMC, and LFMC are all listed for use in wet locations.
Question 6: Under NEC 300.22(C), wiring installed in a plenum ceiling space used for air handling must:
- Use only plenum-rated cables or wiring enclosed in metal conduit (Correct answer)
- Use any cable type since it is above the ceiling tile
- Be installed only in armored cable (AC)
- Be installed in rigid nonmetallic conduit
Correct answer: Use only plenum-rated cables or wiring enclosed in metal conduit
NEC 300.22(C) requires that wiring in air-handling plenums use listed plenum-rated cables or be installed in metal conduit to limit smoke spread.
Question 7: What does NEC 300.15 require at each point where conductors are spliced or terminated?
- Conductors must be soldered at all splice points
- A box, conduit body, or fitting must be installed at each splice or termination point (Correct answer)
- Splices must only be made at the panelboard
- Wire nuts are not permitted for permanent splices
Correct answer: A box, conduit body, or fitting must be installed at each splice or termination point
NEC 300.15 requires a box, conduit body, or fitting to be installed at each point where conductors are spliced or terminated.
TN LLE Wiring Methods and Installation 1
According to NEC Table 300.5, what is the minimum burial depth for Type UF cable used for a 120/240V residential branch circuit?